How to mount two USB devices via USB hub on OTG

A

AC Question

Dear friends,
I have a small problem which I need you to help me.

Is there any software which I can install on my android tablet so that via OTG cable connected to a USB hub I can copy an SDcard via a USB adaptor to an external hard disk.

The problem I have is that only one USB device is mounted when I connect the setup listed above. Is there any file explorer app that can mount both USB devices connected to the USB hub.
for your info, the tablet is rooted and use USB Stick mount app to try and mount both USB devices.